A lane departure avoidance (LDA) system is a type of driver warning system. A LDA system assists the driver in maintaining proper lane alignment by alerting the driver to a possible unintentional lane departure.
A LDA system relies on the detection of the vehicle position with respect to road lane markings in order to detect a lane departure. Different technologies have been applied including primarily vision based systems and other lane sensing methods. In a typical vision based system, the vehicle position is evaluated by a camera and an image processing algorithm wherein an alarm is issued to alert the driver if an abnormal lane departure is detected. Alternatively, a LDA system may include a rumble strip sensing component to detect an amount of rumble strip engagement from a rumble strip to a vehicle wheel. Other technologies include magnetic strips and the like.
A LDA system includes a lane departure detection (LDD) subsystem and a lane departure warning (LDW) subsystem. The LDD subsystem recognizes the lane markings and road edges and estimates the position of the vehicle within the lane. In response to a positive lane departure detection being made, the LDW subsystem uses LDD subsystem information on the basis of a Time to Lane Crossing (TLC) calculation to provide an alert to the driver.
Typical LDW subsystems have been configured to generate audio, visual, and haptic (torque) feedback alerts to the driver in response to detection of an unintentional lane departure. The warning effectiveness and user acceptance of a group of warning methods has been evaluated when unintended lane departures are the result of drowsy driving. The steering wheel vibration HMI (human-machine interface) was found to be an effective HMI for a LDW subsystem in a group of drowsy drivers, with faster reaction times and smaller lane excursions.
Warning subsystems of driver warning systems like the typical LDW subsystems require additional devices to be installed on the vehicle in order to be able to generate the feedback alerts. The requirement for additional devices is especially true for those warning subsystems which generate the haptic vibration feedback alert that was found to be effective.